Guideway structure for high-speed track- bound transportation

ABSTRACT

A guideway structure for high-speed track-bound transportation composed of two or more than two girder-segments. The structure of the guideway is characteristic of: At the intermediate positions on the girder top and the girder bottom of the connecting ends of the said girder-segments are all disposed the pre-embedded steel elements and some anchoring nails used for ensuring the pre-embedded steel elements to be reliably connected with the concrete of girder-segments, after the relevant connecting ends of the two adjacent girder-segments are placed closely, they may be connected together to form a two-span quasi-continuous girder by tightening a plurality of bolts through their respective through hole on the connecting elements and on the pre-embedded elements.

FIELD OF THE INVENTION

The invention relates to track-bound transportation, namely a modernhigh-speed track-bound transportation, and especially relates to aguideway structure suitable for high-speed magnetic levitation (maglev)transportation.

BACKGROUND OF THE INVENTION

The whole track is formed by connecting the guideway girders one by one;each of those is placed across two adjacent supporting columns. For themodern high speed track-bound transportation system such as the maglevtrain, etc. it requires that the guideway must be of extremely highaccuracy, the deformation and the deflection of the guideway due to theinfluence of the factors of temperature difference, dynamic load andetc. must be controlled within a very small range, when the train is inhigh speed running. In the case of the traditional bridges, there is nodifficulty to solve the problems of deflection and the hogging back ofthe girders caused by the temperature difference or dynamic load, but inthe case of the guideway for the running of the modern high-speedtrack-bound vehicle, especially for the running of the maglev train,these small deformations caused by the temperature difference or dynamicload will influence the high-speed running of the train.

Through calculation it is known that in comparison of the structuralfunctions of a continuous girder and two simply supported girders of thesame section, the former has the superiority in the control of thedeformation caused by the temperature difference and the dynamic load.But the guideway with continuous girder structure generally adopts sucha construction mode, i.e. the girders have to be pre-fabricated infactory and then erected on site. Because the size and the weight of thecontinuous girder itself are too big, and in the meantime because themulti-span continuous girder belongs to a multi-point supported externalhyper-static structure, in the process of transporting, lifting andinstalling the multi-span continuous girder must be kept in amulti-point supporting state from the beginning to the end, as well asthe dislocations of any supporting point also must be controlled withina small range in order to ensure the safety of the multi-span continuousgirder itself. If not, the damages of multi-span continuous girder willoccur easily in the whole process of the guideway construction.Therefore in the process of the construction not only a parallel road ofhigh class has to be built along the guideway which is specially usedfor transporting the multi-span continuous girder, simultaneously thespecial carrier for the multi-point supported girders and the cranespecially for the multi-point synchronous lifting must be available.These will bring many difficulties in fabrication, processing,transportation, installation and positioning, as a result, the cost offabrication and construction will greatly increase.

Under the action of temperature difference, all the support reactionforces of continuous girder at intermediate column, whether alongvertical direction or along horizontal direction, generally are quitegreater than those of simply-supported girder. From the view point ofthe viaduct foundation structure, it has a better function for resistingvertical reaction force, the increase of the vertical reaction force isinsensitive to the construction cost of the lower foundation, but itsfunction for resisting horizontal reaction force always is poorer. Eachtime, even a small increase of the horizontal reaction force caused bythe upper structure will make a great increase of the materialconsumption for the lower foundation. It is especially so in the case ofsoft soil foundation.

The German Patent DE19936756 disclosed a method to connect severalsimply-supported type girders to be a continuous girder as shown inFIG. 1. The method of Patent DE19936756 yet is to connect thesesimply-supported type girders to be an entirely continuous girderwhether observing it along vertical direction or observing it alonghorizontal direction, namely it is connected to be a truly continuousgirder. Thus, such a structural mode cannot overcome the disadvantagethat in this case the horizontal support reaction force of thecontinuous girder at the intermediate column is too big, so it is unableto achieve the objective of decreasing the construction cost of thelower foundation.

Additionally, in Patent DE19936756 a mode of embedded guide-screws andtoothed-structure is used for connecting and positioning twosimply-supported girder-segments. Because the guide-screw and thetoothed structure all are embedded and positioned before pouringconcrete or formed during pouring concrete, even though two adjacentsegments of girder are poured at the same time, yet it can only beensured that the positions relative to the concrete structure elementsbetween two adjacent girder-segments are aligned. But for the structureof maglev guideway line or other high-speed track-bound transportation,the accurate positioning of space position means the continuousalignment of the phase positions among all the functional surfaces ofthe track. Moreover, the dimensions and positions of these functionalsurfaces are determined by the successive machining and the accurateassembly carried out after the pre-fabrication of the concrete main bodyof guideway girder has been completed. In this case, the dimensions oforiginal guideway girder structural element had been corrected byreducing or complimentarily adding material, thus the dimensions andpositions of finally-finished functional surfaces of the guideway girderare far different from those of the original concrete girder-segmentstructural element. Hence the method of using embedded guide-screws andtoothed structures of Patent DE19936756, in fact, cannot achieve theobjective for accurately positioning two adjacent girder-segments.

CONTENTS OF THE INVENTION

The technical problem need to be solved by the invention is to overcomethe aforesaid existing technical deficiencies and to provide a guidewaystructure suitable for the high-speed track-bound transportation. To bespecific, connecting a plurality of simply-supported girder-segmentstogether to be a multi-span quasi-continuous girder aims to utilizefully the advantage of the continuous girder that the deformation causedby temperature difference and dynamic load may be controlled to besmaller, and that the difficulties in pre-fabricating, processing,transporting and installing a bigger and heavier continuous girder maybe conquered.

The conception of the invention is that every girder-segment laid acrosstwo adjacent supporting columns of the guideway is fabricated,processed, transported, installed and accurately positioned as asimply-supported girder, then these girder-segments across two spans (ora plurality of spans) are connected together to be a quasi-continuousgirder, which has a structure mode approximate to a continuous girderwith a bending-rigidity as large as possible in vertical plane (i.e. adirection around Y-axis) and has a structure mode approximate to aquasi-continuous girder by a structure mode to hinge-joint many of two-or multi-span simply-supported girder-segments together one by one andwith a bending-rigidity as small as possible along horizontal direction(i.e. a direction around Z-axis).

The Technical Solution is as Follows:

A track structure for high-speed track-bound transportation inclusive oftwo or more than two girder-segments is characteristic of the following:

In the laterally intermediate portions of girder top and girder bottomat the connected ends of girder-segment are disposed the steelpre-embedded elements and many anchoring nails used for ensuring thepre-embedded elements to be reliably connected with the concrete of thegirder-segment. When the connecting end of one girder-segment is placedclose up to that of the other, then these two girder-segments may beconnected to be a quasi-continuous girder by tightening the boltsthrough their respective screw-holes on the connecting elements and thepre-embedded elements;

The aforesaid girder-segment may be a solid one or a hollow one(inclusive of empty chamber 3);

The aforesaid pre-embedded element is a concave-shape steel plate;

On the aforesaid concave-shape embedded element are disposed therolled-wire slant anchors for applying pre-stress;

Furthermore, on the aforesaid concave-shape embedded element for therolled-wire slant anchors also are disposed the horizontal anchor bar;

Additionally, by means of tightly pressing the concave shape embeddedelements in the girder top at connecting end of girder-segment withpost-tensioned prestress reinforcing bar, these two adjacentgirder-segments will be connected more tightly and firmly;

The aforesaid girder-segment is a reinforced concrete girder;

The aforesaid girder-segment is a pestressed concrete girder;

The connection of the aforesaid connecting elements and embeddedelements also may employ the weld connection mode;

If the aforesaid girder-segment is of steel structure, the connectionmechanism may be further simplified, the connecting elements will besimply connected respectively with the top plates or the bottom platesof these two or more than two steel structure girder-segments with boltsor by welding;

The upper and the lower connecting elements are respectively placed atthe inner sides of the upper top plate and the lower bottom plate in thesteel girder chamber;

The aforesaid connecting elements may have various types, e.g. platetype (for connecting steel plates), block type, column type or tubetype.

BRIEF DESCRIPTION OF APPENDED DRAWINGS

FIG. 1 is a schematic diagram of 2-span girder consisting of 2 segmentsof the existing technology.

FIG. 2 is a structural schematic diagram of a guideway girder connectedby two concrete girder-segments in embodiment 1 of the invention.

FIG. 3 is a schematic diagram of embedded element tightly pressed bypost-tensioned reinforcing bar.

FIG. 4 is a plan view of FIG. 2.

FIG. 5 is a locally enlarged schematic diagram of the connecting portionin FIG. 4.

FIG. 6 is a schematic diagram of section along line A-A in FIG. 4.

FIG. 7 is a schematic diagram of section along line B-B in FIG. 4.

FIG. 8 is a structural schematic diagram of guideway girder formed bytwo connected steel girder-segments in embodiment 2 of the invention.

FIG. 9 is a schematic diagram of section along line C-C in FIG. 8.

FIG. 10 is schematic position diagram of steel connecting plate disposedin empty chamber of a steel girder.

In These Figures:

1, 2—girder segments;

3—empty chamber;

4—rolled-wire slant anchor;

5—post-tensioned pre-stressed reinforcing bar;

6—pre-embedded steel connecting element (pre-embedded element);

7—vertical anchoring nail;

8—connecting steel plate;

9—bolt;

10—horizontal anchor bar;

11, 12—steel structure girder-segments;

13—weld-joint place;

14—top plate;

15—bottom plate;

16—weld-joint place.

DESCRIPTION OF THE EMBODIMENTS

FIG. 2 is a schematic structural diagram of the guideway girder formedby two connected concrete girder-segments in embodiment 1 of theinvention. It is a horizontally hinge-jointed and approximate to acontinuous two-span guideway structure in vertical plane. Referring toFIGS. 3 to 7, embodiment 1 is a girder composed of concretegirder-segments 1 and 2. The girder-segment is a hollow girder with anempty chamber 3. In girder-segments are disposed the reinforcing bars.The connection structure between girder-segments 1 and 2 is formed byconcave-shape pre-embedded steel connecting element 6 (briefly calledpre-embedded element), vertical anchoring nails 7 are firmly connectedwith the pre-embedded element 6, connecting steel plate 8 and bolts 9.In embodiment 1, besides the vertical anchoring nail and horizontalanchor bar are designed, the rolled-wire slant anchor, which may applyslant pre-compressive force, is also specially designed in order toresist the horizontal force and the potential upward bending force actedbetween two girder-segments. As shown in FIGS. 4, 5 and 7, the abovestructure can ensure a reliable connection and a reliable forcetransferring between two girder-segments.

For further reliably ensuring the connection and force-transferringbetween pre-embedded element and girder-segment 1 or 2, the anchoringpoints of post-tensioned reinforcing bars 5 at the connecting ends ofgirder-segments 1 and 2 may be moved upward to press against thepre-embedded elements 6. As shown in FIG. 3 it is equivalent to applyinga certain pre-compressive force on the pre-embedded element 6.

The aforesaid pre-embedded elements 6 are respectively disposed ingirder top and girder bottom at the connecting ends of girder-segments 1and 2. The aforesaid connecting steel plates 8, in a total of twopieces, are respectively disposed at intermediate position of girder topand girder bottom at the connecting end of girder, thus girder-segments1 and 2 may be connected together with bolts 9 passing through thecorresponding through-holes on pre-embedded elements 6 and connectingsteel plates 8. By so doing, the vertical spacing between two connectingsteel plates 8 may be as large as possible and they are alsorespectively placed at the intermediate points along the horizontaldirection. Such a structure may ensure that the horizontalbending-rigidity is far less than that in the vertical plane, the formerless than 5% of the latter, and more ideally carrying out the connectionbetween two (or more than two) girder-segments in the vertical plane,approximate to continuous one as well as the connection between each twogirder-segments in horizontal plane still approximate to a hinge-jointof the original design conception. Namely, in vertical plane thegirder-segments are connected together to be a two-span or multi-spancontinuous girder and in horizontal plane each of them is still as asimply-supported girder. The results of calculation and practicalstructure measurement show that: in comparison of the structure of theinvention and that of an entirely continuous multi-span girder, theircharacteristics are quite close in the control of deformation caused bytemperature variation and dynamic load.

In connection mode, the connection between connecting steel plate 8 andpre-embedded steel element 6 may utilize either weld connection mode(weld line 12) or bolt 9 connection mode, the latter may adopt thefinish bolt connection mode or the high strength bolt connection mode.In case that the high strength bolt connection mode is adopted, bothcontact surfaces of the connecting steel plate 8 and concave-shapepre-embedded steel plate 6 have to be processed by sand blasting. Thesand blasting technology must meet the process requirement of thefriction surface for high strength bolt connection of steel structure.

In a certain degree twisting warping and bending deflection maybe existbetween two adjacent girder-segments, especially between twogirder-segments with composite deformation, it will cause twopre-embedded steel plates 6 unable to be laid completely in a same planewith a result in connection that the connecting steel plates 8 cannotclosely contact with them, then the force-transferring will be affectedby it. In this case the shape of relevant connecting steel plate 8 maybe suitably rectified through flame heating in the center and watercooling during construction process to make it closely contact withthese two pre-embedded steel plates 6 of the girder-segments, namely, bymeans of the distorting deformation of steel plate 8 to adapt to thespace positioning of two adjacent girder-segments. This guarantees thatthe displacement of the accurately positioned girder-segments will notoccur because of the connection of girder-segments.

Due to sunshine and ambient temperature variation, the temperaturedifference between the girder top and the girder bottom surfaces existand will cause a hogback deformation of the girder-segments. Undernormal conditions, the temperature of girder top surface is higher thanthat of the girder bottom surface, thus in most cases, the hogbackdeformation is convex upward, its direction is just reverse to that ofdeflect deformation caused by the train dynamic load. If theirmagnitudes are equal, they will be balanced each other. Of course, it isthe most ideal status, so that an optimal comfort can be achieved whenthe train passes through the guideway line with high-speed. But in fact,the deflection is controlled by the bending rigidity of girder itselfand the temperature difference varies with time, seasons and weather,therefore their magnitudes are always different in a certain degree.Because the connection structure of the invention can tightly lock theconnecting steel plates 8 under the condition of a selected temperaturevariation range or a selected girder deflection range, it can play therole of fine adjustment to the above differences, controlling thedeformation difference caused by various factors to a smaller range andachieve the purpose of optimal train comfort.

Although other measures have been taken in the girder design, for areinforced concrete girder, it is difficult to completely avoid theincrease of deflection caused by contraction and creep of concrete astime goes on. After the train has been operated for many years, if thedeflection caused by contraction and creep of concrete is large enoughto affect the requirements of train running, in this case, thefabrication method and the structure of the invention can be adopted.The connections between two adjacent girder-segments may be loosened andthen the relevant connecting steel plates 8 will not be tightly lockedagain until the hogging back of girder caused by temperature differenceis relatively big or the hogging back of girder is increased to acertain magnitude through application of external force. The objectivefor balancing the deflection caused by concrete and creep of concretemay be achieved by this method, and the guideway structure forhigh-speed train in its whole service life may be ensured to meet therequirement on dimensional tolerance for the operation of high-speedtraffic system.

FIG. 8 is a schematic structural diagram of the guideway girder inembodiment 2 of the invention, which is formed by two connected steelgirder-segments 11 and 12. Referring to FIG. 9, the guideway structuremay be further simplified, in this case two adjacent steel girdersegments are able to be connected only by directly connecting therelevant connecting steel plates 8 with their respective top plate 14and bottom plate 15 of the steel girder-segments 11 and 12 with bolt orusing the weld connection mode, thus the pre-embedded elements 6 for theconnection between the concrete girder-segments 1 and 2, as well as thecorresponding anchor elements such as vertical anchoring nails 7,horizontal anchor bars 10 and rolled-wire slant anchor 4 all may beomitted.

For the convenience of installation and no influence on the operationalspace of train, the upper and the lower connecting steel plates 8 alsomay be respectively disposed at the inner side of top plate 14 andbottom plate 15 of the empty chamber 3 of steel girder-segment as shownin FIG. 10.

Synthesizing above description, the improved technical effects of theinvention are as follows:

1. A quite difficult technical problem in respect of the fabrication,transportation and installation of the big and heavy multi-span guidewaygirder may be conquered and the construction cost of modem high-speedtrack-bound transportation, especially that of maglev guideway may bequite greatly saved, because each of girder-segments of guideway may bepre-fabricated, processed, transported, installed and accuratelypositioned as simply-supported girders and then two or more than twogirder-segments may be connected together to be a two-span or multi-spanquasi-continuous guideway girder with the connection mechanism.

2. The connection mechanism of girder-segments of the invention is onecomposed of pre-embedded elements respectively disposed on girder topand girder bottom of girder-segment's connecting ends, or composed oftwo connecting steel plates respectively disposed on girder top andgirder bottom of girder-segment's connecting ends, as a result thevertical spacing between the two connecting plates can be as large aspossible and in lateral plane they are respectively placed atintermediate positions of girder-segment's connecting ends, able toensure the bending rigidity of the connection in lateral plane is farsmaller than that in vertical plane. In other words, in vertical planethe girder-segments are connected together to be a two-span ormulti-span quasi-continuous girder but in horizontal plane each ofgirder-segments is still kept as a simply-supported girder connectedwith other adjacent ones;

3. The connection mechanism of the invention relatively is simple andable to provide a convenient condition for repair and maintenance infuture.

The above only exemplifies the optimal embodiments of the invention andthe connection of a two-span girder-segments is described as an example.That does not mean that the structure of the invention may bepopularized to the connection of multi-span girder-segments. It cannotbe understood that the present invention is limited to these exemplifiedembodiments and relevant descriptions. Any simple modifications in theapplication of the conception and the structure of the present inventionbelong to the scope of protection of the present invention.

1. A guideway structure for high-speed track-bound transportation comprising two or more girder-segments, wherein the guideway structure further comprises: pre-embedded elements disposed on a girder top surface and a girder bottom surface of connecting ends of said girder-segments, anchoring nails associated with said pre-embedded elements to additionally fasten the pre-embedded elements to concrete parts of said girder-segments, and connecting elements configured to be placed in a horizontal direction across said connecting ends of adjacent said girder-segments, wherein the connecting ends of adjacent said girder-segments are configured to be connected together to form a quasi-continuous girder by a plurality of fasteners configured to pass through the connecting elements and the pre-embedded elements; and wherein said pre-embedded elements are concave-shaped plates.
 2. The guideway structure for high-speed track-bound transportation of claim 1 wherein on said concave-shaped plates are also disposed rolled-wire slant anchors for applying prestress.
 3. The guideway structure for high-speed track-bound transportation of claim 2 wherein on said concave-shaped plates with rolled-wire slant anchors thereon are also disposed horizontal anchor bars.
 4. The guideway structure for high-speed track-bound transportation of claim 3 wherein said concave-shaped plates respectively placed on the girder top surfaces of said connecting ends of said girder-segments are pressed tightly by a post-tensioned prestress reinforcing bar in order that said pre- embedded elements can be further firmly connected respectively with said girder- segments.
 5. The guideway structure for high-speed track-bound transportation of claim 1 wherein said girder-segment is a reinforced concrete girder.
 6. The guideway structure for high-speed track-bound transportation of claim 1 wherein said girder-segment is a prestressed reinforced concrete girder.
 7. The guideway structure for high-speed track-bound transportation of claim 1 wherein a weld connection mode may also be used for the connection of the said connecting elements and the said pre-embedded elements. 